Magnetostrictive materials, particles in particular, may be used inside a porous medium to change the porosity or permeability properties within the medium. Such materials or particles may be called magnetopropants, alluding to the effect of changing the interstitial volume by exerting force on the matrix of the medium by the change in the shape of the magnetostrictive material. To effect shape change, the magnetostrictive material must be exposed to a magnetic field. It is not always practical to supply a controllable magnetic field of sufficient strength at locations where it is desired to actuate the magnetostrictive material. For instance, it is difficult to supply a controllable magnetic field in a geologic formation at a distance far from a well bore.
Acoustic stimulation in a geologic formation has been generally limited to inducement of a selection of wave shapes, sweeps, or simply pounding of drill pipe. For example, sine waves of selected frequencies have been used to loosen the geologic formation in the immediate proximity of a well bore. Although the simple selection of wave shape and frequency may be a simple approach to acoustic stimulation, different geologic formations, hydrocarbon reservoir properties, and near-well-bore conditions create a complex set of circumstances. These complex circumstances require more sophisticated acoustic wave patterns which are characterized by more than selection of wave shape and frequency.